Study On The Mechanism Of Enhancing The Activity Of Suspended Titanium Dioxide Photocatalytic Materials

TiO₂ is an important semiconductor photocatalyst material,which can degrade a variety of organic pollutants under solar ultraviolet light,and finally achieve complete mineralization.At the same time,because of its low cost,non-toxic,no secondary pollution and other advantages,it has attracted the attention of researchers in various countries.It is found that the ion doping modification can overcome these defects to some extent and is an important means to improve the photocatalytic activity of TiO₂.In this study,a certain amount of neodymium ion doped nano titanium dioxide crystals were prepared by the sol-gel method,and loaded onto the micron sized hollow glass beads S60HS,as well as three methods of adding the template PEG4000 to optimize the modification of TiO₂,improve the photocatalytic efficiency of TiO₂ under ultraviolet light,and facilitate recycling.In order to improve the performance of the catalyst,a series of characterization methods such as determination of hydroxyl radical concentration,PL spectroscopy,FT-IR spectroscopy,BET,etc.were used in the research process.The specific contents of this experiment are as follows:1.The 5%Nd-TiO₂ prepared by sol gel method with tetrabutyl titanate as titanium source and neodymium nitrate pentahydrate as neodymium source,after aging,drying,grinding,and heating rate of 5℃/min,calcination at 450℃for 3h,has the highest photocatalytic activity.By comparison,5%Nd-TiO2 has the highest photocatalytic activity within the doping concentration range set in the experiment.Compared with TiO₂,5%Nd-TiO₂ has larger specific surface area,but smaller average pore diameter and slightly smaller pore volume.It may be that the doping of neodymium makes 5%Nd-TiO₂ form smaller grains and better dispersion than TiO₂ particles.2.With hollow glass bead S60HS as the carrier,the density of 5%Nd-TiO₂/S60HS after loading decreased significantly.Through comparison of different loads,the comprehensive evaluation shows that 5%Nd-TiO₂（30%）/S60HS is the best when the load of TiO₂ is 30%.Its density is close to that of water,0.96 g/cm³.It can float in the solution,which is conducive to the recovery and utilization of the catalyst.In order to test the service life of 5%Nd-TiO₂（30%）/S60HS,the photocatalytic activity was compared for five cycles.3.Using PEG4000 as template,the effect of different PEG4000 dosage on the activity of5%Nd-TiO₂ photocatalyst was investigated.The photodegradation rates of 5%Nd-TiO₂（PEG4000）3g and 5%Nd-TiO₂ on active brilliant red X-3B were 76.1%and 43.1%,respectively;However,after five cycles,their photodegradation rates for active brilliant red were 56.1%and 18.1%,respectively,indicating that 5%Nd-TiO₂（PEG4000）3g still maintained good photocatalytic activity and its recycling performance was good.